Dressing device

ABSTRACT

The invention relates to a transparent, absorbent device for the dressing of wounds and insertion sites of percutaneous and drug delivery devices. The device provides 360 degree or complete circumferential protection of a wound or insertion site of a percutaneous or drug delivery device and comprises a hydrogel center and at least one absorbent material. The hydrogel center can optionally comprise a bioactive agent(s).

FIELD OF THE INVENTION

The invention relates to a transparent, absorbent device for thedressing of wounds and insertion sites of percutaneous and drug deliverydevices. In particular, the device provides 360 degree or completecircumferential protection of a wound or insertion site of apercutaneous or drug delivery device and comprises a hydrogel center andan absorbent material surrounding the hydrogel center.

BACKGROUND OF THE INVENTION

Hospitals employ multiple strategies to prevent and/or reduce woundinfections and infections associated with the use of percutaneous anddrug delivery medical devices, such as antiseptic preparation of woundsand insertion sites. Such strategies include the initial application oftopical antimicrobial solutions such as alcohol or iodine. Topicalointments, such as ointments containing neomycin, polymyxin andbactracin, and dressing devices have also been shown to prevent woundinfections and catheter colonization/infection.

Many types of dressings are known for the treatment of wounds andinsertion sites of percutaneous and drug delivery devices. Cuffsimpregnated with an antimicrobial agent have been used to attach tocatheters. Johnson & Johnson Corporation markets a commerciallyavailable cuff product sold under the trade mark BIOPATCH® that isapplied around percutaneous devices to prevent localized infection atthe insertion site. This product is a foam material that contains theantimicrobial agent chlorhexidine gluconate (CHG). Efforts to coat thecatheters with antimicrobial agents are also known.

Recently transparent film dressings, that allow a visual check on acatheter insertion site, have been used as described in U.S. Pat. No.5,372,589, issued Dec. 13, 1994 to Davis. Centurion Medical Productsmarkets a commercially available catheter site dressing withantimicrobial properties sold under the trademark SorbaView® SHIELD. The3M Company also markets a commercially available intravenous (IV) sitetransparent dressing sold under the trademark Tegaderm™-CHG(clorhexidine gluconate) that is designed to reduce the incidence ofcatheter-related bloodstream infections (CRBSI), with the CHG being theantimicrobial agent. The CHG is intended to elute from a pad that istransparent and covered with an adhesive bandage layer. The device,however, fails to provide 360 degree or complete circumferentialcoverage around the insertion site, and the CHG eluting portion of thedevice is not placed underneath the catheter which may further limit itseffectiveness. The device transparency is also compromised when placedin an area with oozing blood and/or exudates.

Securement devices are also known, such as U.S. Pat. No. 3,918,446,issued Nov. 11, 1975 to Buttaravoli, that assist with keeping apercutaneous device in place. The device of U.S. Pat. No. 3,918,446 hasan upper and a lower pad, between which the intravenous device is fixed.Since the function of the device is to secure the device to the body,there is a teaching to provide an adhesive material to the bottom oflower pad, and to the bottom of the top pad. U.S. Pat. No. 3,918,446discusses providing the adhesive with an antibacterial agent, and thedevice of this patent teaches including a slit in the bottom pad of thedressing, which lies below the intravenous needle or catheter when thedevice is in place, allowing the intravenous device to remain in contactwith the skin, and therefore limiting the infection control of thedevice.

U.S. Pat. No. 5,833,665 issued to Matthew Bootman et al. is directed toa wound dressing for percutaneous catheters that is comprised of a crosslinked polymer containing a bioactive agent. U.S. Pat. No. 5,833,665discloses a radial slit that is made in the device so that it can bedeployed over an already placed catheter. It also discloses and claimsthe use of adhesives for securing the device.

U.S. Pat. No. 6,368,611 entitled “Anti-infective covering forpercutaneous and vascular access device and coating method” and issuedto Whitbourne discloses a device comprising a disc provided with anantimicrobial composition, wherein the composition comprises at leastone antimicrobial agent exhibiting antimicrobial activity when in asubstantially dry state or when solvated after being in a substantiallydry state. The disc surrounds and abuts an inserted surface of aninsertable medical device when a portion of the inserted surfaceprojects from a bodily surface; the disc is in contact with the bodilysurface.

In addition to infection control and transparency, there is a need forabsorbent dressings to wick away blood and exudates. U.S. patentapplication Ser. No. 10/515,028 entitled “Ionic hydrogels withcontrolled aqueous fluid absorption” and published on Mar. 30, 2006, asU.S. Patent Publication No. 2006/0068014 A1 discloses cross-linkedplasticized polymeric hydrogels suitable for use in skin contactingapplications that can be used in association with medical, health andpersonal care products such as passive drug delivery devices and wounddressings.

U.S. patent application Ser. No. 13/054,208 entitled “Compositions foruse as or in wound dressings” and published on Aug. 4, 2011, as U.S.Patent Publication No. 2011/0190722 A1 discloses a composition for thetreatment of a wound wherein the composition comprises a first layer,which comprises a porous, optionally hydrophilic material capable ofabsorbing fluid from the wound at least in part by capillary action, anda second layer comprising an absorbent hydrogel. The first layer isassociated with the second layer, and, in the treatment, the first layeris disposed closer to the wound than the second layer.

U.S. patent application Ser. No. 11/840,536 entitled “Absorbentmaterials and articles” and published on Dec. 6, 2007, as U.S. PatentPublication No. 2007/0282237 A1 discloses an absorbent material thatcomprises a flexible, skin-conformable, moisture-absorbent sheet member,optionally a net member in sheet form overlying and associated with theabsorbent sheet member on at least one face thereof, and a hydrogeldisposed on at least one of the net member, when present.

A number of other patents teach various types of related dressings,including U.S. Pat. No. 4,324,237 to Buttaravoli; U.S. Pat. No.5,571,079 to Bello et al.; U.S. Pat. No. 5,686,096 to Khan; U.S. Pat.No. 6,765,122 to Stout; U.S. Pat. No. 7,137.968 to Burell; and U.S. Pat.No. 7,858,838 to Holm et al. A number of other patents teach varioussingle slit embodiments, such as U.S. Pat. Nos. 4,915,694; 5,554,106;5,620,419; 5,968,000; 6,765,122; and 7,723,559. Other related referencesinclude U.S. Pat. No. 6,787,682 entitled “Absorbent foam wound dressing”and issued to Gilman; U.S. Pat. No. 6,124,521 entitled “Dermal woundwindow dressing securement system” and issued to Roberts; and U.S. Pat.No. 6,884,920 entitled “Hydrocolloid window catheter dressing and amethod for making and using the same” and issued to Worthley.

There is a need, however, to provide an improved exudates absorbingdevice for complete or 360 degree or complete circumferential protectionof a wound or percutaneous or drug delivery device insertion site. It isan object of the present invention to provide wound dressing devicehaving transparency for inspecting the conditions of the wound or skinpenetration site and absorbency to wick away blood and exudates toprevent maceration of the skin and the reduction in the transparency tothe wound site. It is another object of the present invention to providea dressing device having a transparent hydrogel center and an absorbentmaterial to wick away blood and remove exudates wherein the hydrogelcenter can optionally comprise a bioactive agent to deliverantimicrobial and/or other wound healing factors at the wound site orsite of the insertion of a percutaneous or drug delivery device into thebody.

These and other objects of the present invention will be apparent fromthe following description and appended claims, and from practice of theinvention.

SUMMARY OF THE INVENTION

The present invention is directed to a wound dressing for use with apercutaneous or drug delivery device that has punctured the skin of apatient and which has a portion of the percutaneous medical deviceprotruding from the skin. One type of such a percutaneous device is acatheter, such as a temporary installed catheter or longer termin-dwelling catheter. The dressing of the present invention provides animproved exudates absorbing function for 360 degree or completecircumferential protection of a wound or percutaneous or drug deliverydevice insertion site, with the device having transparency forinspecting the conditions of surgical wound and/or of the skinpenetration site and sufficient absorbency to effectively wick awayblood and exudates. The device can optionally comprise antimicrobialproperties.

In one embodiment, the wound dressing comprises a transparent hydrogelcenter and an absorbent material surrounding a periphery of thetransparent hydrogel center. In some embodiments, the wound dressing isadapted for use with a percutaneous or drug delivery medical device thathas punctured the skin of a patient and has a portion of thepercutaneous or drug delivery medical device protruding from the skin.In these embodiments, the wound dressing further comprise an aperture inthe hydrogel center and a slit connecting a periphery of the absorbentmaterial with the aperture. In other embodiments, the hydrogel centercan further comprise a bioactive agent(s). In other embodiments, thewound dressing can further comprise an optional barrier coating orbarrier film in order to prevent migration of the bioactive agent intothe absorbent material. In yet another embodiment, the hydrogel centerfurther comprises a hemostatic coating. In another embodiment, thehydrogel center comprises a plurality of surface channels to carryexudates by capillary action towards the absorbent material.

In another embodiment, the wound dressing comprises a transparenthydrogel center; a first absorbent material layer comprising an internalportion, a peripheral portion, and a centrally disposed aperture; and asecond absorbent material layer comprising an internal portion, aperipheral portion, and a centrally disposed aperture. In thisembodiment, the first and second absorbent material layers are joinedtogether at the peripheral portions of the first and second absorbentmaterial layers and a gap is formed between the first and secondabsorbent material layers at the internal portions of the first andsecond absorbent material layers. The hydrogel center is disposed in thecentrally disposed apertures of the first and second absorbent materiallayers and a periphery portion of the hydrogel center is within the gapformed between the first and second absorbent material layers. In thisdouble absorbent material layer embodiment, the hydrogel center freefloats in the gap between the first and second absorbent materiallayers, and the wound dressing can be adapted for use with apercutaneous or drug delivery medical device that has punctured the skinof a patient and has a portion of the percutaneous or drug deliverymedical device protruding from the skin. In these embodiments, the wounddressing further comprise an aperture in the hydrogel center and a slitconnecting a periphery of the absorbent material with the aperture.

In another embodiment of the double absorbent material layer embodiment,the hydrogel center further comprises a bioactive agent(s) and/or ahemostatic coating. In another embodiment, the hydrogel center comprisesa plurality of surface channels to carry exudates by capillary actiontowards the absorbent material. In yet another embodiment of the doubleabsorbent material layer embodiment, the wound dressing comprises atransparent film disposed between the hydrogel center and the absorbentmaterial of the first and second layers to prevent sticking of thehydrogel center to the first and second absorbent material layers.

The material used for the absorbent material and absorbent materiallayers of the wound dressings discussed herein comprise a woven ornon-woven felt or foam selected from the group consisting ofpolyurethane, polyester, cellulose, alginate, polyacrylates,polyolefins, and cottons. The hydrogel centers of the wound dressings ofthe invention comprise a hydrogel material selected from the groupconsisting of polyethylene oxide, polypropylene oxide, poloxamer,2-acrylamido-2methypropane sulphonic acid, 3-sulphopropylacrylate,polyvinylpyrrolidone, polyethylene glycol, polylactic acid,polyvinylalcohol, polyacrylamides, silicone, agarose, methylcellulose,hyaluronan, collagen-acrylate, and polyethylene glycol co-peptides.

The bioactive agents suitable for use with the wound dressings of theinvention comprise one or more antimicrobial agents selected from thegroup consisting of chlorhexidine gluconate, chlorhexidine acetate,silver iodide, silver bromide, silver chloride, nano-particulatemetallic silver, benzalkonium chloride, polyhexamethylene biguanide,Triclosan, metronidazole, alcohol, or iodine.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 a illustrates a perspective view of an embodiment of a dressingdevice according to the present invention.

FIG. 1 b illustrates a cross section view of the device shown in FIG. 1a.

FIGS. 2 a-2 f illustrate perspective views of variously shapedembodiments of dressing devices according to the present invention.

FIG. 3 a illustrates a perspective view of another embodiment of theinventive dressing device shown in FIG. 1 a further comprising anaperture in the center and a slit connecting a periphery of the devicewith the aperture.

FIG. 3 b illustrates a cross section view of another embodiment of theinventive dressing device shown in FIG. 1 a further comprising anaperture in the center.

FIG. 3 c illustrates a top view of another embodiment of the inventivedressing device shown in FIG. 1 a with an optional slit in non-linear orcurved configuration.

FIGS. 4 a-4 c illustrate perspective views of various embodiments of theinventive dressing device comprising an aperture in the center and aslit connecting a periphery of the device with the aperture.

FIG. 5 illustrates a cross section view of another embodiment of adressing device according to the present invention.

FIGS. 6 a and 6 b illustrate cross section views of another embodimentof the inventive dressing device shown in FIG. 5 further comprising atransparent film between the hydrogel center and the absorbentmaterials.

FIG. 7 illustrates a cross section view of an embodiment of theinventive dressing device further comprising a barrier coating or film.

FIG. 8 is a schematic of an embodiment of the inventive dressing devicedressing the insertion site of a percutaneous medical device.

FIG. 9 a illustrates a perspective view of another embodiment of theinventive dressing device according to the present invention.

FIG. 9 b illustrates a cross section view of the device shown in FIG. 9a.

DETAILED DESCRIPTION OF THE INVENTION

It is an object of the present invention to provide an improved exudatesabsorbing device to serve as dressings for wounds and insertion sites ofpercutaneous and drug delivery devices. The device of the presentinvention provides 360 degree protection of wounds or insertion sites ofpercutaneous or drug delivery devices and comprises a hydrogel centerand an absorbent material surrounding the hydrogel center for wickingaway blood and exudates. The device of the present invention hastransparency for inspecting the conditions of the skin penetration siteand can optionally have antimicrobial properties.

It is an object of the present invention to provide a wound dressingthat is easily applied and is made of a polymer which can serve as adelivery vehicle for controlled release of a bioactive agent entirelyaround a wound or insertion site of a percutaneous or drug deliverydevice. These and other objects of the invention will be apparent fromthe following description and appended claims and from practice of theinvention.

Referring to FIG. 1 a, illustrated is a perspective view of anembodiment of a dressing device 10 according to the present inventioncomprising a transparent or semi-transparent hydrogel center 20 that canoptionally be impregnated with a bioactive agent. In one embodiment, thebioactive agent is an antimicrobial agent. The hydrogel center 20 issurrounded in its periphery 22 by an absorbent material 30 made of foam,fabric, non-woven, or fiber structure or other suitable material. In oneembodiment, the hydrogel center 20 and absorbent material 30 aredisposed side-by-side. In this embodiment, for example, the hydrogel canbe attached to the absorbent material by pouring a polyethylene oxide(PEO), hydrogel feed mix gel (AquaMed Technology Inc.) into a foamcavity and cross linking the PEO. The hydrogel center 20 is formed in ashape of a substantially flat disk of circular or elliptical shape. Theabsorbent material 30, such as polyurethane foam, can be attached to thehydrogel center 20 by having an oversized supportive scrim, typical ofthat used in the industry, so that the scrim could be spot welded, gluedor crimped onto the absorbent material or foam. In FIG. 1 b, a crosssectional view of the embodiment shown in FIG. 1 a is illustrated.

In one embodiment, the absorbent material 30 is used as a mold duringcasting of the hydrogel to create an integrated structure. In anotherembodiment, the absorbent material 30 and the hydrogel center 20 areattached to one another by a supporting structure such as scrim or otherfilm layer coating. In another embodiment, there is a circular void orcut-out in the absorbent material 30 into which the hydrogel center 20is inserted. In another embodiment, the hydrogel can be cut to a 16 mmdiameter disk and placed in a slit within the absorptive material 30,such as polyurethane foam. The slit sides of the absorbent material 30are designed to hold the hydrogel center 20 in intimate contact with theskin. In one embodiment, the hydrogel is shaped on a contour that placesa significant portion of the hydrogel center imbedded within theabsorptive material 30.

As illustrated in FIGS. 2 a-2 f, which show perspective views ofvariously shaped embodiments of a dressing device according to thepresent invention, other geometrical shapes of the hydrogel center 20are contemplated such as circular, elliptical, rectangular, star-shaped,and other shapes. The outer absorbent material 30, formed by die-cuttingfoam, fabric, non-woven, or fiber structure or other suitable materialto a thickness of 1 mm to 4 mm and in a circular or elliptical shape,surrounds the periphery 22 of the hydrogel center 20. In one embodiment,the absorbent material 30 is disposed side-by-side with the hydrogelcenter 20, and in another embodiment the absorbent material 30 overlapsthe hydrogel center 20 by 1 mm to 3 mm. Other geometrical shapes of theouter absorbent material 30 are contemplated such as rectangular,elliptical, star-shaped, and other shapes as illustrated in FIGS. 2 a-2f. In all embodiments, the periphery 22 of the hydrogel center 20 isfully surrounded by the outer absorbent material 30.

FIG. 3 a illustrates a perspective view of another embodiment of theinventive dressing device 10 shown in FIG. 1 a further comprising anaperture 40 in the center and a slit 50 connecting a periphery 32 of theabsorbent material 30 or device 10 with the aperture 40. FIG. 3 billustrates a cross section view of another embodiment of the inventivedressing device shown in FIG. 1 b further comprising an aperture in thecenter. The aperture 40 and slit 50 can be formed by cutting, punching,or similar after the dressing device 10 is constructed. FIG. 3 cillustrates a top view of another embodiment of the inventive dressingdevice shown in FIG. 1 a with an optional slit in non-linear or curvedconfiguration, which can be zigzag, angled, kidney-shaped.

The embodiments illustrated in FIGS. 3 a, 3 b, and 3 c are adapted foruse with a percutaneous or drug delivery medical device (not shown) thathas punctured the skin of a patient and has a portion of thepercutaneous or drug delivery medical device protruding from the skin.One type of such a percutaneous device is a catheter, such as atemporary installed catheter or longer term in-dwelling catheter. Thedressing device 10 of the present invention is adapted for installationover a site of the insertion of the catheter into the body by having anoptional aperture 40 for accommodating the catheter and an optional slit50 for facilitating the installation of the dressing device over thecatheter. The dressing device 10 provides an improved exudates absorbingfunction for 360 degree or complete circumferential protection of thecatheter insertion site, with the device having transparency forinspecting the conditions of the skin penetration site and sufficientabsorbency to effectively wick away blood and exudates. The dressingdevice 10 can also provide improved antimicrobial function for 360degree protection of a wound or catheter insertion site by havingantimicrobial properties.

The aperture 40 has a shape and diameter to accommodate the percutaneousor drug delivery medical device protruding from the skin. In oneembodiment, the diameter of the circular aperture 40 is equal to theoutside diameter of a catheter or is larger than the outside diameter ofa catheter by 0.001 mm-1 mm. In some embodiments, the diameter ofaperture 40 is from about 0.3 mm to about 15 mm. In another embodiment,the diameter of aperture 40 is from about 1 mm to about 8 mm. The widthof slit 50 is adapted to facilitate installation over the alreadyinstalled indwelling catheter. The width of slit 50 ranges from about0.01 mm to about 2 mm. In another embodiment, the width of slit 50ranges from about 0.1 mm to 1.0 mm. The slit 50 of the device can becreated after loading of the hydrogel center 20 with a bioactiveagent(s) and attaching the absorbent material 30 to the hydrogel center20.

As illustrated in FIGS. 4 a-4 c, which show perspective views of otherembodiments of the invention, several configurations of the aperture 40and of the slit 50 for accommodating a percutaneous or drug deliverymedical device are contemplated.

Referring to FIG. 5, a cross sectional side view of another embodimentof a dressing device 10 according to the present invention is shown. Theembodiment illustrated in FIG. 5 comprises a transparent hydrogel center20. The hydrogel center 20 can optionally comprise a bioactive agent.The embodiment in FIG. 5 further comprises an outer first absorbentmaterial layer 35 and an outer second absorbent material layer 37. Thefirst and second absorbent material layers 35 and 37 each comprise anabsorbent woven or non-woven fabric; an internal portion 29 and 31; aperipheral portion 33 and 34; and a centrally disposed aperture 38 and39. The first and second absorbent material layers 35 and 37 allow forexpansion and contraction of the hydrogel center 20 and render a lowdressing profile with a height from about 1 mm to about 5 mm. In anotherembodiment, the profile of the dressing device 10 is about 2 mm to about3 mm.

The first and second absorbent material layers 35 and 37 are joinedtogether at the peripheral portions 33 and 34 of the first and secondabsorbent material layers 35 and 37, and a gap 36 is formed between thefirst and second absorbent material layers 35 and 37 at the internalportions 29 and 31 of the first and second absorbent material layers 35and 37. The hydrogel center 20 is disposed in the centrally disposedapertures 38 and 39 of the first and second absorbent material layers 35and 37 and the periphery portion 22 of the hydrogel center 20 is withinthe gap 36 formed between the first and second absorbent material layers35 and 37.

As can be seen in FIG. 5, the hydrogel center 20 in its peripheral part22 is positioned and free floats between first and second absorbentmaterial layers 35 and 37. Layers 35 and 37 are joined in the peripheralportions 33 and 34 of the first and second absorbent material layers 35and 37 and form a gap 36 between the first and second absorbent materiallayers 35 and 37 at the internal portions 29 and 31 of the first andsecond absorbent material layers 35 and 37. The first and secondabsorbent material layers 35 and 37 can expand upon absorption ofexudates and upon swelling of hydrogel. The hydrogel center 20 freefloats between the two layers 35 and 37 of the absorbent material, whichallows the hydrogel center 20 to keep its adherence to skin contourafter swelling. The ratio of diameters of the hydrogel center 20 andabsorbent material layers 35 and 37 and the highly fractious nature ofabsorbent material layers 35 and 37 allow the hydrogel center 20 toremain in the centrally disposed apertures 38 and 39 of the first andsecond absorbent material layers 35 and 37. In one embodiment, the ratioof diameters of the hydrogel center 20 to the absorbent material layers35 and 37 is 1:2. In one embodiment, the outer absorbent material layers35 and 37 are formed by two non-woven Dacron® polyester felt rings(commercially available from DuPont Inc.) needle-punched together in theperipheral portions 33 and 34 of the first and second absorbent materiallayers 35 and 37. The expansion gap 36 slidably engages the hydrogelcenter 20 in the periphery portion 22 of the hydrogel center 20.

While the prior art discloses using hydrogels attached to other layersto provide strength, and/or improve the function or securement of thehydrogel, allowing the hydrogel center 20 to free float between the twolayers 35 and 37 of absorbent material improves the functionalcharacteristics of the hydrogel center 20 and allows the hydrogel center20 to adhere to the skin contour to provide 360 degree protection ofwounds and insertion sites of percutaneous and drug delivery devices.Specifically, the design of the embodiment illustrated in FIG. 5 allowstwo or more dissimilar materials to optimally function at a closeproximity without interfering or contaminating one another. Theabsorbent material of the first and second layers 35 and 37 can wickaway wound exudates and swell without being constrained or deformed bythe hydrogel center 20, and the hydrogel center 20 can control therelease of bioactive agent(s) independent of the absorbent material.This embodiment also allows the hydrogel center 20 to be loaded with abioactive agent(s) independent of interference from the absorbentmaterial.

In the embodiment illustrated in FIG. 5, the inventive dressing device10 would indicate the need for a dressing change when the firstabsorbent material layer 35 reveals moisture, exudates, or blooddiscoloration. This is a result of the design of the embodimentillustrated in FIG. 5, said design requiring the moisture and/orexudates to travel from the hydrogel center 20 to the second absorbentmaterial layer 37, which is in contact with the surface of the wound orinsertion site, prior to traveling to the first absorbent material layer35. There is a large absorbance difference between the hydrogel center20 and the absorbent material of the first and second layers 35 and 37that allows the fluid to flow to the absorbent material from thehydrogel center 20. The two-layer design of the dressing device 10 inwhich the hydrogel center 20 separates the first and second absorbentmaterial layers 35 and 37 allows the moisture and/or exudates to travelfrom layer 37 to layer 35. When the appearance of layer 35 changes, thedressing is fully or almost fully saturated from moisture and/orexudates, thus indicating a time for dressing change.

The absorbent material of the first and second absorbent material layers35 and 37 is used to surround the hydrogel center 20. When the dressingdevice 10 is placed on a wound or insertion site the moisture and/orexudates is wicked in a horizontal direction until the limit of theouter diameter of the hydrogel center 20. At the outer diameter of thehydrogel center 20, the moisture and/or exudates can make intimatecontact with the first absorbent material layer 35. This results inlayer 35 having a moisture ring.

Referring to FIGS. 6 a and 6 b, illustrated are cross sectional views ofanother embodiment of the inventive dressing device 10 shown in FIG. 5further comprising an optional transparent film 60 between the hydrogelcenter 20 and the first and second absorbent material layers 35 and 37.The transparent film 60 prevents sticking of the hydrogel center 20 tothe absorbent material of the first and second layers 35 and 37, andcomprises a semi-permeable polyurethane material such as film DM 4004and DM 4007 from DermaMed Coatings Company, LLC, Hydrothane AR25-85Afrom CT Biomaterials, semi-permeable polyurethane from the 3M Company,or comparable materials. Other suitable materials include plasticrelease covers, nylon mesh and coated mesh. The transparent film 60 canbe applied post casting and cross linking of the hydrogel. The thicknessof the transparent film 60 film is from about 0.03 mm to 0.25 mmdepending on the moisture permeability and support required for themedical or hygiene application the dressing is intended for. In anotherembodiment, the thickness of the transparent film 60 is between 0.05 mmand 0.15 mm.

In the embodiment shown in FIG. 6 a, the transparent film 60 is disposedin the form of rings between peripheral portion 22 of the hydrogelcenter 20 and the peripheral portions 33 and 34 of the first and secondabsorbent material layers 35 and 37 leaving the central area 21 of thewound contacting side of the hydrogel center 20 open for wound contact.The film is in the form of rings that are precut or stamped to allow thehydrogel center 20 to be removed prior to application to the wound orpuncture site. The transparent film 60 rings can be placed on thehydrogel center 20 prior to the hydrogel center 20 being positionedbetween the first and second absorbent material layers 35 and 37. Thetransparent film 60 adheres to the hydrogel center 20 as a result of theadherent nature of the transparent film 60 material. In the embodimentshown in FIG. 6 b, the optional transparent film 60 is fully coveringone side of hydrogel center 20 including the non-wound facing side ofthe hydrogel center 20 and the peripheral portion 22, while leavingcentral area 21 of the wound contacting side of the hydrogel center 20open for wound contact. The central area 21 of the wound contacting sideof the hydrogel center 20 can be unveiled by removing an optionalprotective film covering 75 from the central area of the hydrogel priorto the placement of the dressing device 10 on the wound or puncturesite.

The embodiments illustrated in FIGS. 5 and 6 can also be adapted for usewith a percutaneous or drug delivery medical device that has puncturedthe skin of a patient and has a portion of the percutaneous or drugdelivery medical device protruding from the skin by further comprisingan aperture and slit as discussed above. In one embodiment, the dressingdevice is assembled and then the optional slit 50 (not shown in FIG. 5or 6) is cut radially through the hydrogel center 20 and the first andsecond absorbent material layers 35 and 37. In another embodiment, thereis an overlapping flap on the first absorbent material layer 35 withoptional attachment (not shown).

Referring now to FIG. 7, illustrated is a cross sectional view of anembodiment of the inventive dressing device 10 with the hydrogel center20 at least partially overlapping the absorbent material 30, with theoverlap being from 10 percent to about 40 percent of the overalldiameter of the device. In another embodiment, the hydrogel center 20overlaps about 30 percent of the overall diameter of the device. Theembodiment illustrated in FIG. 7 further comprises an optional barriercoating or barrier film 70 disposed at an interface between hydrogelcenter 20 and absorbent material 30. This optional barrier coating orbarrier film 70 prevents migration of the bioactive agent into theabsorbent material and comprises a polypropylene film having thicknessof about 12.5 microns to about 125 microns. In this embodiment, thesecurement of the hydrogel to the absorbent material is achieved bypartial overlap of the hydrogel over the absorbent material with theoptional barrier. For example, a polyethylene oxide (PEO) hydrogel feedmix gel (AquaMed Technology Inc.) can be poured into a foam cavity,overlapping the hydrogel over the absorbent material with the optionalbarrier and cross linking the PEO.

The embodiment illustrated in FIG. 7 can also be adapted for use with apercutaneous or drug delivery medical device that has punctured the skinof a patient and has a portion of the percutaneous or drug deliverymedical device protruding from the skin by further comprising anaperture and slit as discussed above.

Referring now to FIG. 8, a schematic view of the inventive dressingdevice 10 is shown with a percutaneous or drug delivery medical device100 that has punctured the skin of a patient (not shown) and which has aportion of the percutaneous medical device 100 protruding from the skin.The optional slit 50 facilitates placement of the dressing device 10around the percutaneous device 100. Optional dressing 200 for fixatingthe dressing device is fixating the dressing device 10 to the skin ofpatient.

One type of such a percutaneous device 100 is a catheter, such as atemporary installed catheter or longer term in-dwelling catheter.

As illustrated in FIG. 9 a, the hydrogel center 20 can further comprisesurface channels 23 to carry exudates by capillary action towards theabsorbent material. In one embodiment, the surface channels have a depthof 0.1-5 mm and a width of 0.1-5 mm. In another embodiment, the surfacechannels have a depth of 0.5-1 mm and a width of 0.5-2 mm. The channelsare cut into the hydrogel center 20 post casting or alternatively castinto the hydrogel center 20. In FIG. 9 b, a cross sectional view of theembodiment shown in FIG. 9 a is illustrated. These surface channels 23are optional for all embodiments discussed herein, FIGS. 1-7.

In another embodiment, the inventive dressing devices 10 describedherein have an optional integrated transparent covering or fixation filmto attach the dressing device 10 to the skin of a patient. Suitablecovering or fixation films are known and available, for example the 3MCompany's Tegaderm Absorbent Clean Acrylic Dressing.

In yet another embodiment, the inventive dressing devices 10 describedherein further comprise a hemostatic coating, such as non-cross-linkedpolyethylene oxide (PEO), with the hemostatic coating disposed on thewound contacting surface of the hydrogel center 20 and/or the woundcontacting surface of the absorbent material 30. In another embodiment,the hemostatic coating is dispersed in the hydrogel center 20 and/or theabsorbent material 30. In the embodiment illustrated in FIGS. 5 and 6,the wound contacting surface of the hydrogel center 20 and/or the woundcontacting second absorbent material layer 37 can optionally be coatedwith a hemostatic coating, or the hemostatic coating can be dispersed inthe hydrogel center or coated on the first and/or second absorbentmaterial layers 35 and 37. The hemostatic coating can be on a supportivefiber scrim (or mesh) which supports the hydrogel by being eitherincorporated into the hydrogel or bound to the surface of the hydrogel.The coating can be for example, a very thin coating of PEO having amolecular weight above about 600,000 daltons. A description of thiscoating, the coating of this material, and the hemostatic efficacy canbe reviewed in U.S. Pat. No. 4,616,644 issued to Saferstein et al. andentitled Hemostatic Adhesive Bandage.

In another embodiment, the inventive dressing devices 10 describedherein can comprise a fiber scrim or mesh to support the hydrogelcenter. In another embodiment, the hemostatic coating can be placed on afiber scrim or mesh that is supporting the hydrogel center. In anotherembodiment, the hemostatic agent is dispersed or dissolved in thehydrogel. In an alternative embodiment, the film or mesh is made fromthe polyethylene oxide. In yet another embodiment, the polyurethanesponge or comparable absorbing material is coated with the highmolecular weight polyethylene oxide. Other suitable materials for theoptional hemostatic coating include collagen, chitosan, thrombin,gelatin, polylactic-co-glycolic acid, glycosaminoglycans/hyaluronicacid, hyaluronan, polyphenols, and comparable materials. Methods forapplication of a PEO coating for hemostatic applications are described,for example, in U.S. Pat. No. 4,616,644 by Saferstein et al.

Materials

The hydrogel center 20 is made of any tissue compatible hydrogelmaterial such as polyethylene oxide (PEO), polypropylene oxide,poloxamer, 2-acrylamido-2methypropane sulphonic acid (AMPS),3-sulphopropylacrylate (SPA), polyvinylpyrrolidone (PVP), polyethyleneglycol (PEG), polylactic acid (PLA), polyvinylalcohol (PVA),polyacrylamides, silicone, agarose, methylcellulose, hyaluronan,collagen-acrylate, and polyethylene glycol (PEG) co-peptides. In oneembodiment, the hydrogel material comprises PVP. In another embodiment,the hydrogel material comprises PVP with PEG and PEO.

The hydrogel material is preferably fully or partially transparent tofacilitate observation of wound conditions. The hydrogel center hasmoisture wicking and absorptive properties with the ionic gels of thehydrogel material being able to take up moisture at an accelerated rate.This rate and capacity is less than one observes with absorbent fibersand sponges, which work by physical wicking and will release themoisture when pressure is applied. Hydrogels chemically bond themoisture and will not release the moisture with a pressure application.

The hydrogel center 20 typically does not adhere to the insertion sitedue to the nature of the material. The inventive dressing devicerequires an occlusive dressing that will help prevent microbial ingressbut allow for oxygen and vapor transmission. The hydrogel can beengineered to stick intimately to the wound site by incorporatingpolystyrene nanoparticles into the hydrogel.

In one embodiment, the hydrogel material is prepared by the steps ofcross-linking a polymer that contains chemically reactivefunctionalities that react with a cross-linking reagent, where thecross-linking agent comprises greater than two reactive sites permolecule that are chemically reactive with functionalities on thepolymer to form a cross-linked polymer. The polymers that are to bereacted with a cross-linking agent can include PVP/PEG 0.03 inch, 10percent PEO 0.055 inch thickness, and 5.5 percent PEO 0.055 inch thick(available from AquaMed Technologies Inc.) A PEG hydrogel material canbe produced, for example, by reacting poly(ethyleneglycol)-dimethacrylate (PEGDM) with a photoinitiator exposed to 365 nmultraviolet light.

NU-GEL® Wound Dressing is an occlusive hydrogel sheet dressingconsisting of preserved polyvinyl pyrrolidone in water. This formulationallows the dressing to absorb 50 percent more exudate than traditionalhydrogel dressings, and is commercially available from Johnson&JohnsonWound Management a division of ETHICON, INC. Somerville N.J. First WaterLimited (Marlborough, Wiltshire UK) also markets a commerciallyavailable ionic hydrogel wound dressing.

The hydrogel center 20 can be formed by molding or casting beforecross-linking or by cutting after cross-linking. The cross-linkedpolymer can then be loaded with a desired bioactive agent(s). Afterbeing formed into the desired shape, the cross-linked polymer iscontacted with a bioactive agent to reversibly bind the bioactive agentto the cross-linked polymer to form the polymeric delivery vehicle.Typically, the bioactive agent is dissolved in a suitable solvent andthen placed in fluid contact with the cross-linked polymer by immersion.The loading of the polymer, which can be a synthetic or biopolymer ormixture thereof, (optionally cross-linked polymer) may be readilydetermined based upon the uptake of the polymer of the bioactive agent.In one embodiment, the bioactive agent is dissolved in water at asuitable concentration, typically about 1 tot percent by weight, and thecross-linked polymer is immersed therein for a period of about 20minutes to 60 hours. In one embodiment, the cross-linked polymer isimmersed for about 5-10 hours. At ambient temperature, about 20-25degrees Celsius, the polymer is then extracted from the solvent, allowedto air dry or lyophilized, and then ready for use. The polymer ispartially dry in about 2 to about 100 hours, typically 20-60 hours atambient temperature. The time to hydrate the polymer is typically about2 to 24 hours.

Alternatively, the cross-linked polymer may be loaded with a bioactiveagent, then dried and cut to a suitable form for use. In anotherembodiment, the bioactive agent and polymer are dissolved in an aqueoussolvent before cross-linking and the bioactive agent is bound to thepolymer. Typical agent:polymer weight ratios are in the range of about1:100 to 5:100 in solution. In another embodiment, the agent:polymerweight ratios range is 3:100. The polymer is then cross-linked bytreatment with the cross-linking agent.

The antimicrobial or bioactive agent that can be incorporated in thehydrogel center 20 can be a chlorhexidine compound, for instancechlorhexidine gluconate or chlorhexidine acetate; silver compounds, forinstance silver iodide, silver bromide, silver chloride, ornano-particulate metallic silver; benzalkonium chloride;polyhexamethylene biguanide (PHMB); triclosan; antibiotics such asmetronidazole; alcohol; iodine; or other known antimicrobial compoundsand combinations thereof that are compatible with skin and usefulagainst a range of microorganisms, for example against known skin florasuch as Staphylococcus aureus and methicillin-resistant Staphylococcusaureus (MRSA). In one embodiment, the bioactive agent is chlorhexidinegluconate, an agent known to be safe and effective and widely used as asurgical disinfectant. Plasticizers, colorants, surfactants, andstabilizers, singular or in combination, can also be incorporated in thehydrogel center.

The outer absorbent material 30 and first and second absorbent materiallayers 35 and 37 are made of any tissue compatible absorbent woven ornon-woven material or foam. The absorbent material may comprise a felt,such as polyurethane foam; polyester mats, such as DACRON® polyesterfiber mats that are commercially available from DuPont, Inc.; natural,synthetic, or hybrid synthetic/natural polyester; cellulose; alginate;polyacrylates; polyolefins; and cottons.

The thickness of the polymeric matrix may be varied as desired,depending upon the desired pharmaceutical dosage and duration ofdelivery. Ordinarily, a suitable matrix thickness will be in a range ofabout 0.25 to 5 mm. In one embodiment, the suitable matrix thickness is0.5 mm to 1.5 mm.

In one embodiment, the diameter of the dressing device ranged from 2 cmto 10 cm with a ratio of diameters of the hydrogel center to absorbentmaterial at approximately 1:2. In another embodiment, such as thatillustrated in FIG. 5, the dressing device is 1 mm thick with an outsidediameter of 50 mm and an inside diameter of 25 mm, and the hydrogelcenter 20 is 0.4 mm thick with an outside diameter of 35 mm. In anotherembodiment, the wound facing side of the hydrogel center has a 20 to 25mm area where a polyethylene protective film would be removed prior towound application.

Percutaneous Medical Devices

Percutaneous medical devices for which the dressing devices of thepresent invention can be used include catheters, pins, implants, and thelike which pass through the skin and are indwelling for someconsiderable time. Exemplary of percutaneous medical devices are centralvenous catheters, peripheral venous catheters, Swan-Ganz pulmonarycatheters, central nervous system implants, such as external ventriculardrainage and ventricular reservoirs, peritoneal dialysis catheters, suchas for continuous ambulatory peritoneal dialysis and continuous cyclicperitoneal dialysis, hemodialysis catheters, transvenous pacemakerleads, and temporary orthopedic pins. All of these percutaneous medicaldevices, when in place, have a portion of the device that is externaland left protruding from the skin, which can be the cause of infectionaround the insertion sites of the medical devices.

Method

The present invention also relates to a method of dressing the woundsite or the insertion site of a percutaneous or drug delivery medicaldevice for a patient using such a device. The inventive dressing devicecan optionally have a bioactive agent that is incorporated into thedevice and/or onto the lower or wound/skin facing surfaces of thedevice, wherein the device is secured to the surface of skin andoptionally to the percutaneous medical device with the help of anadhesive overdressing layer preferably in the form of adhesive thin filmor adhesive bandaging tape.

When used over a wound, the dressing device 10 is applied by positioningthe device over the wound with the hydrogel center 20 facing the woundand in contact with the wound, and the outer absorbent material 30 (orfirst and second absorbent material layers of the embodiment illustratedin FIGS. 5 and 6) on the periphery of the wound or surrounding thewound, with any blood and exudates absorbed by the absorbent outermaterial 30.

When used over a percutaneous or drug delivery medical device, thedressing device 10 is applied by positioning the dressing device withthe hydrogel center 20 facing the skin and with the percutaneous or drugdelivery device guided through the slit 50 and into the aperture 40,enabling the dressing device to fully surround the catheter at theinsertion or puncture site. The hydrogel center 20 is thereby in contactwith the skin surrounding the puncture site. Advantageously, thedressing device enables nurses and physicians to position the dressingdevice over a previously installed or secured percutaneous or drugdelivery medical device, such as a catheter. The dressing deviceprovides 360 degree or complete circumferential coverage around thecatheter shaft and for a length greater than the diameter of thecatheter shaft. In one embodiment, the dressing device is elasticallyresilient and it can be attached to the catheter without using anadhesive or additional dressing. In another embodiment, the dressingdevice has antimicrobial properties wherein the hydrogel center 20comprises a bioactive agent(s).

The following examples are illustrative of the principles and practiceof this invention, although not limited thereto. Numerous additionalembodiments within the scope and spirit of the invention will becomeapparent to those skilled in the art once having the benefit of thisdisclosure.

Example 1 Materials

Antimicrobial dressing devices as illustrated in FIG. 5 were assembledusing several types of hydrogel materials: hydrogel from AquamedTechnologies PVP/PEG 0.03 inch, 10 percent PEO 0.055 inch thickness, 5.5percent PEO 0.055 inch thick; hydrogel from NU-GEL® Wound Dressing whichis an occlusive hydrogel sheet dressing consisting of preservedpolyvinyl pyrrolidone in water; and ionic hydrogel from First WaterWiltshire in UK. The three types of hydrogels were used to assemble theinventive devices, but only the devices with Nu-Gel hydrogel were usedto test the anti-microbial properties.

Two DACRON® nonwoven polyester mats were used for the first and secondabsorbent material layers.

Preparation of First and Second Absorbent Material Layers with a Gap

To make approximately 50 prototype devices, appropriate quantities ofDacron® nonwoven polyester mats, obtained from DuPont Inc., were cut tosize having a thickness of 1 mm thick (but thicknesses of from about 0.5mm to about 2.5 mm can be utilized), a diameter of 50 mm, and a 20 mmcentrally disposed aperture. For each prototype device, two Dacron®nonwoven polyester mats were melded together by needle punching in theirperipheral portions to bring the mats into intimate contact to allowmoisture to transverse the layers and to remain integral duringapplication and throughout treatment duration. A gap or sock likestructure was formed between the two layers at their internal portions.The barb needle was able to combine the two layers together byinterspersing the non woven fibers between the two layers.

Preparation of the Hydrogel Material with a Bioactive Agent

One way of loading the hydrogel material with a bioactive agent(s) isadding the bioactive agent(s) into the feed mix (which is thenon-cross-linked hydrogel material) and mixing until fully homogeneousprior to cross-linking. The cross-linking is then performed by anymethods known to these skilled in the art, e.g. UV, e-beam, thermal,etc. In the instant invention, the commercial hydrogel was used andprepared by cutting to a specific size.

The hydrogel material for the hydrogel center was cut to form a 3.5 cmdiameter disk and then loaded with 40 mg CHG. Specifically, CHG in a 20%CHG solution in water was loaded on a Nu-GEL® Wound Dressing which is apolyvinyl pyrrolidone hydrogel supported by a supportive fiber scrim (ormesh) with a polyethylene film on both outer surfaces. The hydrogel wasremoved from the sterile foil package and had the bottom protectivepolyethylene film removed to allow partial dehydration to take place.The hydrogel was stored at ambient conditions and allowed to lose about8 to 10% of its equilibrium weight. 2 ml of the CHG solution wasdistributed on the hydrogel surface and allowed to be drawn in. Thehydrogel was then observed to recover to its original hydrated weight.

Octendine 20% in EtOH solution was loaded on another Nu-GEL® WoundDressing. The hydrogel was removed from the sterile foil package and hadthe bottom protective polyethylene film removed to allow partialdehydration to take place. The hydrogel was stored at ambient conditionsand allowed to lose about 8 to 10% of its equilibrium weight. 2 ml ofthe Octendine 20% EtOH solution was distributed on the hydrogel surfaceand allowed to be drawn in. The hydrogel was then observed to recover toits original hydrated weight.

PHMB 20% solution in water was loaded on another Nu-GEL® Wound Dressing.The hydrogel was removed from the sterile foil package and had thebottom protective polyethylene film removed to allow partial dehydrationto take place. The hydrogel was placed at ambient conditions and allowedto lose about 8 to 10% of its equilibrium weight. The PHMB 20% solutionin water was distributed on the hydrogel surface and allowed to be drawnin. The hydrogel was then observed to recover to its original hydratedweight.

20% CHG in water+Octendine 20% solution in ethanol was loaded on anotherNu-GEL® Wound Dressing. The hydrogel was removed from the sterile foilpackage and had the bottom protective polyethylene film removed to allowpartial dehydration to take place. The hydrogel was placed at ambientconditions and allowed to lose about 8 to 10% of its equilibrium weight.The 20% CHG+Octendine 20% solution was then distributed on the hydrogelsurface and allowed to be drawn in. The hydrogel was then observed torecover its original hydrated weight.

Assembly of the Device

At least 50 hydrogel centers prepared as discussed above were disposedin the centrally disposed apertures of the first and second absorbentmaterial layers made of Dacron® nonwoven polyester mats (prepared asdiscussed above). The periphery portion of the hydrogel center freefloats within the gap formed between the first and second absorbentmaterial layers. To ensure the hydrogel remained hydrated, the assembleddevice was placed in a foil pouch. Sterilization would be by radiation.

ZOI Study

Two prototypes were then evaluated in a Zone of Inhibition (ZOI) study.The ZOI assay was performed on a Tryptic soy agar (TSA) plate with 6Log/plate by surface inoculation. ZOI was defined as distance inmillimeters between the edge of the device and edge of the no growthzone. Sustained efficacy against S. aureus was tested by daily transferto a new inoculated plate. The tested devices, both loaded with CHG asthe bioactive agent, demonstrated sustained in vitro efficacy of 7 daysagainst S. aureus as shown in Table 1. Two samples utilizing Nu-Gelhydrogel were tested, and the results in Table 1 are an average of thetwo samples.

TABLE 1 Zone of Inhibition against S. aureus Time ZOI (mm) S. aureusDay-1 6.6 Day-2 6.3 Day-3 5.9 Day-4 5.1 Day-5 4.8 Day-6 4.5 Day-7 3.8

Example 2

Ten prototype devices made as described in Example 1 were evaluated forblood or serum absorbency when positioned on fresh pig skin. The sampleswere not loaded with bioactive agent, and the hydrogel used was Nu-Gel.Pig skin was dried with paper towels, cut into 8×8 cm squares, andplaced into Petri dishes. Various and clinically relevant volumes ofblood or serum were added on the center of the pig skin squares, thenBIOPATCH® or a prototype device was applied on top of the fluid. Thefluid absorption time and device appearance were observed and recorded.

The results of one typical test on one device are shown in Table 2. Theprototypes showed equivalent or better absorbency compared to theBIOPATCH® cuff commercially marketed by Johnson & Johnson Corporation.The hydrogel center remained transparent after the prototype devicesabsorbed whole blood or serum to the point of saturation. The rate ofabsorption of the prototype is comparable to that of BIOPATCH®. Theobserved rate of absorption for both BIOPATCH® and the prototype devicewas about 2 g of blood or serum per minute.

TABLE 2 BIOPATCH ® Prototype Device Weight (g) 0.3447 g 1.3522 g Appliedon top of complete absorption in completely absorbed in 2 ml blood 1 min1 min, center visible Applied on top of complete absorption incompletely absorbed in 3 ml blood 1.5 min 1.5 min, center visibleApplied on top of abort 0.5 ml left after completely absorbed in 4 mlserum 2 min and saturation 1.5 min, center visible

The invention being thus described, it will be apparent that the samemay be varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

We claim:
 1. A wound dressing comprising: a transparent hydrogel center,and an absorbent material surrounding a periphery of the transparenthydrogel center.
 2. The wound dressing of claim 1, further comprising anaperture in the hydrogel center and a slit connecting a periphery of theabsorbent material with the aperture.
 3. The wound dressing of claim 2,wherein the aperture is in a central portion of the hydrogel center. 4.The wound dressing of claim 2, wherein a diameter of the aperture isfrom about 0.3 mm to about 15 mm.
 5. The wound dressing of claim 2,wherein a width of the slit is from about 0.01 mm to about 2 mm.
 6. Thewound dressing of claim 2, wherein the slit is non-linear.
 7. The wounddressing of claim 1, wherein the absorbent material comprises a woven ornon-woven felt or foam selected from the group consisting ofpolyurethane, polyester, cellulose, alginate, polyacrylates,polyolefins, and cottons.
 8. The wound dressing of claim 1, wherein thehydrogel center comprises a hydrogel material selected from the groupconsisting of polyethylene oxide, polypropylene oxide, poloxamer,2-acrylamido-2methypropane sulphonic acid, 3-sulphopropylacrylate,polyvinylpyrrolidone, polyethylene glycol, polylactic acid,polyvinylalcohol, polyacrylamides, silicone, agarose, methylcellulose,hyaluronan, collagen-acrylate, and polyethylene glycol co-peptides. 9.The wound dressing of claim 1, wherein the hydrogel center and theabsorbent material are disposed side-by-side.
 10. The wound dressing ofclaim 1, wherein the hydrogel center further comprises a hemostaticcoating.
 11. The wound dressing of claim 10, wherein the hemostaticcoating is disposed on a wound contacting surface of the hydrogelcenter.
 12. The wound dressing of claim 10, wherein the hemostaticcoating is non-cross-linked polyethylene oxide.
 13. The wound dressingof claim 1, wherein the hydrogel center comprises a bioactive agent. 14.The wound dressing of claim 13, wherein the bioactive agent comprisesone or more antimicrobial agents selected from the group consisting ofchlorhexidine gluconate, chlorhexidine acetate, silver iodide, silverbromide, silver chloride, nano-particulate metallic silver, benzalkoniumchloride, polyhexamethylene biguanide, Triclosan, metronidazole,alcohol, or iodine.
 15. The wound dressing of claim 13, wherein thebioactive agent is chlorhexidine gluconate.
 16. The wound dressing ofclaim 13, wherein the hydrogel center partially overlaps the absorbentmaterial and a barrier coating is disposed at an interface between thehydrogel center and the absorbent material.
 17. The wound dressing ofclaim 16, wherein the barrier coating comprises a polypropylene filmhaving thickness of about 12.5 microns to about 125 microns.
 18. Thewound dressing of claim 1, wherein the hydrogel center further comprisesa plurality of surface channels.
 19. The wound dressing of claim 1,wherein the hydrogel center is formed in a circular shape and theabsorbent material is formed in a circular shape.
 20. A wound dressingcomprising: a transparent hydrogel center comprising a peripheryportion; a first absorbent material layer comprising: an internalportion; a peripheral portion; and a centrally disposed aperture; and asecond absorbent material layer comprising: an internal portion; aperipheral portion; and a centrally disposed aperture; wherein the firstand second absorbent material layers are joined together at theperipheral portions of the first and second absorbent material layersand a gap is formed between the first and second absorbent materiallayers at the internal portions of the first and second absorbentmaterial layers; wherein the hydrogel center is disposed in thecentrally disposed apertures of the first and second absorbent materiallayers and the periphery portion of the hydrogel center is within thegap formed between the first and second absorbent material layers. 21.The wound dressing of claim 20, further comprising an aperture in thehydrogel center and a slit connecting the peripheral portions of thefirst and second absorbent material layers with the aperture in thehydrogel center.
 22. The wound dressing of claim 21, wherein a diameterof the aperture in the hydrogel center is from about 0.3 mm to about 15mm.
 23. The wound dressing of claim 21, wherein a width of the slit isfrom about 0.01 mm to about 2 mm.
 24. The wound dressing of claim 21,wherein the slit is non-linear.
 25. The wound dressing of claim 20,wherein the first and second absorbent material layers comprise a wovenor non-woven felt or foam selected from the group consisting ofpolyurethane, polyester, cellulose, alginate, polyacrylates,polyolefins, and cottons.
 26. The wound dressing of claim 20, whereinthe hydrogel center comprises a hydrogel material selected from thegroup consisting of polyethylene oxide, polypropylene oxide, poloxamer,2-acrylamido-2methypropane sulphonic acid, 3-sulphopropylacrylate,polyvinylpyrrolidone, polyethylene glycol, polylactic acid,polyvinylalcohol, polyacrylamides, silicone, agarose, methylcellulose,hyaluronan, collagen-acrylate, and polyethylene glycol co-peptides. 27.The wound dressing of claim 20, wherein the hydrogel center free floatsin the gap between the first and second absorbent material layers. 28.The wound dressing of claim 20, wherein the hydrogel center comprises abioactive agent.
 29. The wound dressing of claim 28, wherein thebioactive agent comprises one or more antimicrobial agents selected fromthe group consisting of chlorhexidine gluconate, chlorhexidine acetate,silver iodide, silver bromide, silver chloride, nano-particulatemetallic silver, benzalkonium chloride, polyhexamethylene biguanide,Triclosan, metronidazole, alcohol, or iodine.
 30. The wound dressing ofclaim 28, wherein the bioactive agent is chlorhexidine gluconate. 31.The wound dressing of claim 20, wherein the hydrogel center furthercomprises a plurality of surface channels.
 32. The wound dressing ofclaim 20, wherein the hydrogel center further comprises a hemostaticcoating.
 33. The wound dressing of claim 32, wherein the hemostaticcoating is disposed on a wound contacting surface of the hydrogelcenter.
 34. The wound dressing of claim 32, wherein the hemostaticcoating is non-cross-linked polyethylene oxide.
 35. The wound dressingof claim 20 further comprising a transparent film disposed between thehydrogel center and the first and second absorbent material layers. 36.The wound dressing of claim 35, wherein the transparent film is in theform of rings.